Thirteen lots of the nasal spray pandemic influenza A(H1N1) vaccine have been recalled because of slightly decreased potency.
The recall of the affected batches of MedImmune's Influenza A (H1N1) 2009 Monovalent Vaccine Live, Intranasal is not safety related, but a result of routine, ongoing stability testing. Last month, the company notified the Centers for Disease Control and Prevention and the Food and Drug Administration that the potency of the 13 lots of nasal spray vaccine had decreased below a prespecified limit or was at risk of falling below that limit.
MedImmune sent providers directions for returning any unused vaccine from the following lots: 500754P, 500751P, 500756P, 500757P, 500758P, 500759P, 500760P, 500761P, 500762P, 500763P, 500764P, 500765P, 500776P. Approximately 4.7 million doses in these lots were distributed in the United States.
Much of the vaccine had already been administered while fully potent. All the vaccine in the affected lots is still expected to be effective in stimulating a protective response, and there is no need to readminister a dose to those who already received vaccine from these lots.